U.S. patent application number 14/094588 was filed with the patent office on 2015-01-15 for insulating film for printed circuit board and product manufactured by using the same.
This patent application is currently assigned to SAMSUNG ELECTRO-MECHANICS CO., LTD.. The applicant listed for this patent is SAMSUNG ELECTRO-MECHANICS CO., LTD.. Invention is credited to Jun Ho Bae, Ho Hyung Ham, Eui Jung Jung, Ki Seok Kim, Hwa Young Lee, Ji Hye Shim.
Application Number | 20150014028 14/094588 |
Document ID | / |
Family ID | 52276225 |
Filed Date | 2015-01-15 |
United States Patent
Application |
20150014028 |
Kind Code |
A1 |
Lee; Hwa Young ; et
al. |
January 15, 2015 |
INSULATING FILM FOR PRINTED CIRCUIT BOARD AND PRODUCT MANUFACTURED
BY USING THE SAME
Abstract
Disclosed herein are an insulating film for a printed circuit
board, a resin coated copper (RCC), a flexible copper clad laminate
(FCCL), and a printed circuit board manufactured by using the same.
More specifically, the RCC, the FCCL, and the printed circuit board
manufactured by using the insulating film for the printed circuit
board according to the preferred embodiment of the present
invention, the insulating film including an insulating layer, and a
primer layer formed on one surface of the insulating layer and
including a benzocyclobutene (BCB)-based resin, may have a low
coefficient of thermal expansion and high peel strength.
Inventors: |
Lee; Hwa Young; (Suwon,
KR) ; Ham; Ho Hyung; (Suwon, KR) ; Bae; Jun
Ho; (Suwon, KR) ; Kim; Ki Seok; (Suwon,
KR) ; Jung; Eui Jung; (Suwon, KR) ; Shim; Ji
Hye; (Suwon, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG ELECTRO-MECHANICS CO., LTD. |
Suwon |
|
KR |
|
|
Assignee: |
SAMSUNG ELECTRO-MECHANICS CO.,
LTD.
Suwon
KR
|
Family ID: |
52276225 |
Appl. No.: |
14/094588 |
Filed: |
December 2, 2013 |
Current U.S.
Class: |
174/257 ;
428/336; 428/413; 428/461; 428/523 |
Current CPC
Class: |
H05K 3/387 20130101;
B32B 2307/714 20130101; Y10T 428/31938 20150401; B32B 2307/308
20130101; H05K 2201/0141 20130101; H05K 2201/0269 20130101; Y10T
428/31511 20150401; B32B 15/092 20130101; H05K 1/0373 20130101;
H05K 2201/0209 20130101; H05K 2201/068 20130101; Y10T 428/31692
20150401; B32B 2307/206 20130101; B32B 27/38 20130101; B32B 27/42
20130101; B32B 2457/08 20130101; B32B 15/06 20130101; Y10T 428/265
20150115; B32B 27/20 20130101; B32B 15/08 20130101; B32B 15/085
20130101; H05K 3/4661 20130101; B32B 2264/10 20130101; B32B
2264/102 20130101 |
Class at
Publication: |
174/257 ;
428/523; 428/413; 428/336; 428/461 |
International
Class: |
H05K 1/02 20060101
H05K001/02; B32B 15/085 20060101 B32B015/085 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 9, 2013 |
KR |
10-2013-0080517 |
Claims
1. An insulating film for a printed circuit board comprising: an
insulating layer; and a primer layer formed on one surface of the
insulating layer and including a benzocyclobutene (BCB)-based
resin.
2. The insulating film as set forth in claim 1, wherein the
insulating layer includes a liquid-crystal oligomer, an epoxy
resin, and an inorganic filler, and the primer layer includes the
benzocyclobutene (BCB)-based resin and the epoxy resin.
3. The insulating film as set forth in claim 2, wherein the
insulating layer includes the liquid-crystal oligomer in an amount
of 4 to 30 wt %, the epoxy resin in an amount of 5 to 30 wt %, and
the inorganic filler in an amount of 40 to 90 wt %.
4. The insulating film as set forth in claim 2, wherein the primer
layer includes the benzocyclobutene (BCB)-based resin in an amount
of 50 to 80 wt % and the epoxy resin in an amount of 20 to 50 wt
%.
5. The insulating film as set forth in claim 2, wherein the primer
layer includes the benzocyclobutene (BCB)-based resin in an amount
of 60 to 70 wt % and the epoxy resin in an amount of 30 to 40 wt
%.
6. The insulating film as set forth in claim 2, wherein the epoxy
resin included in the insulating layer or the primer layer is at
least one selected from a group consisting of a naphthalene-based
epoxy resin, a bisphenol A type epoxy resin, a phenol novolak epoxy
resin, a cresol novolak epoxy resin, a rubber-modified epoxy resin,
a phosphorus-based epoxy resin and a bisphenol F type epoxy
resin.
7. The insulating film as set forth in claim 2, wherein the
inorganic filler is at least one selected from a group consisting
of silica (SiO.sub.2), alumina (Al.sub.2O.sub.3), silicon carbide
(SiC), barium sulfate (BaSO.sub.4), talc, clay, mica powder,
aluminum hydroxide (AlOH.sub.3), magnesium hydroxide
(Mg(OH).sub.2), calcium carbonate (CaCO.sub.3), magnesium carbonate
(MgCO.sub.3), magnesium oxide (MgO), boron nitride (BN), aluminum
borate (AlBO.sub.3), barium titanate (BaTiO.sub.3), calcium
zirconate (CaZrO.sub.3), and a combination thereof.
8. The insulating film as set forth in claim 2, wherein the
inorganic filler included in the insulating layer has a
concentration gradient in a thickness of the insulating layer, and
has a higher concentration distribution in a region distant from
the primer layer than in a region adjacent to the primer layer in
the insulating layer.
9. The insulating film as set forth in claim 1, wherein the primer
layer has a thickness in a range of 1 .mu.m to 3 .mu.m.
10. The insulating film as set forth in claim 2, wherein the
insulating layer or the primer layer further includes a curing
agent, a curing accelerator, or a combination thereof.
11. The insulating film as set forth in claim 10, wherein the
curing agent is at least one selected from a group consisting of an
amine-based curing agent, an acid anhydride-based curing agent, a
polyamine curing agent, a polysulfide curing agent, a phenol
novolak type curing agent, a bisphenol A type curing agent and a
dicyandiamide curing agent.
12. The insulating film as set forth in claim 10, wherein the
curing accelerator is at least one selected from a group consisting
of a metal-based curing accelerator, an imidazole-based curing
accelerator, and an amine-based curing accelerator.
13. The insulating film as set forth in claim 1, wherein the primer
layer is formed by directly applying a primer solution on the
insulating layer or casting the primer solution on a carrier film
and then laminating and transferring the primer solution on the
insulating layer.
14. A resin coated copper (RCC) or a flexible copper clad laminate
(FCCL) manufactured by stacking and laminating copper clad layers
on the primer layer of the insulating film for a printed circuit
board as set forth in claim 1.
15. A printed circuit board manufactured by stacking and laminating
the resin coated copper (RCC) or the flexible copper clad laminate
(FCCL) as set forth in claim 14 on a substrate having a circuit
pattern formed therein.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of Korean Patent
Application No. 10-2013-0080517, filed on Jul. 9, 2013, entitled
"Insulating Film for Printed Circuit Board And Product Manufactured
by Using the Same", which is hereby incorporated by reference in
its entirety into this application.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The present invention relates to an insulating film for a
printed circuit board and a product manufactured by using the
same.
[0004] 2. Description of the Related Art
[0005] As an electronic device has a small size and a high
performance, a multilayer printed circuit board has been demanded
to have a high density, a high function, a small size, and a thin
thickness. Accordingly, a printed circuit board mounting various
electronic components has been gradually fine-patterned according
to meeting demands for the thin film and high integration.
[0006] In particular, in order to develop wire to be miniaturized
and have high density, a process in which an insulating film
without a glass cloth is built-up to form a circuit by a
semi-additive process (SAP) or a modified semi-additive process
(MSAP) scheme instead of a process for forming the insulating layer
of a prepreg type in which the glass cloth is impregnated has
increasingly used. In addition, the build-up layer of the
multilayer printed circuit board has multilayers.
[0007] In addition, thermal, mechanical, and electrical properties
in a build-up insulating film replacing the prepreg (PPG) and an
insulating layer of the multilayer printed circuit board are also
important factors. The insulating layer has been demanded to have a
low coefficient of thermal expansion, a high glass transition
temperature, and a modulus property in order to minimize warpage
generated by a reflow in a mounting process of an electronic device
or an electrical device.
[0008] Recently, various methods for improving thermal, mechanical,
and electrical properties of the insulating layer of the build-up
layer which is used in the multilayer printed circuit board used in
the electronic device according to the development of the
electronic device have been studied. Among the various methods, an
inorganic filler is filled in the insulating layer in order to
achieve high peel strength, a low dielectric constant, and a low
coefficient of thermal expansion, and therefore, a content of the
inorganic filler has been gradually increased according to the
demand of the printed circuit board. However, the increased content
of the inorganic filler may cause defects in a circuit process and
deterioration in reliability.
[0009] For example, Patent Document 1 discloses a primer layer
formed by using an aromatic polyamide-based resin, a thermosetting
resin, and a filler particle in order to solve the above-described
problems. Here, an epoxy resin, a cyanate resin, benzocyclobutene,
or the like, is used as the thermosetting resin.
[0010] In the printed circuit board according to the prior art, a
circuit layer is formed by a plating process, wherein a desmear
(roughening plating) process for forming illuminance by etching a
surface of the insulating layer using a potassium permanganate
solution in order to increase a plating adhesion between the
circuit layer and the insulating layer is performed. Here, since an
organic matrix portion is selective removed in the desmear process
including swelling, etching, and neutralization, in the case in
which the content of the inorganic filler is increased in the
insulating film, large amounts of inorganic fillers remain on the
surface of the insulating layer after the desmear process. The
inorganic filler exposed on the surface of the insulating layer
decreases the plating adhesion between the insulating layer and the
circuit layer, causing defects in the circuit process and
deterioration in the reliability.
[0011] In other words, according to the recent trend, the filling
content of the inorganic filler is increased in the insulating
layer, such that it is difficult to achieve the peel strength
between the circuit layer and the insulating layer, and in the case
in which the filling content of the inorganic filler is decreased
in order to achieve the peel strength, the coefficient of thermal
expansion of the insulating layer is not sufficiently small.
[0012] Therefore, a method for maintaining the thermal expansion
property of the insulating layer and securing the plated adhesion
is required.
PRIOR ART DOCUMENT
Patent Document
[0013] Patent Document 1 Korean Patent Laid-Open Publication No.
2012-0021243
SUMMARY OF THE INVENTION
[0014] In the present invention, it is confirmed that an insulating
film for a printed circuit board including an insulating film and a
primer layer formed on one surface of the insulating layer and
including a benzocyclobutene (BCB)-based resin and a product
manufactured by using the same have a low coefficient of thermal
expansion and high peel strength, thereby completing the present
invention.
[0015] Therefore, the present invention has been made in an effort
to provide the insulating film for the printed circuit board having
the low coefficient of thermal expansion and the high peel
strength.
[0016] In addition, the present invention has been made in an
effort to provide a resin coated copper (RCC) or a flexible copper
clad laminate (FCCL) manufactured by stacking copper clad layers on
one surface or both surfaces of the insulating film.
[0017] Further, the present invention has been made in an effort to
provide a printed circuit board manufactured by stacking the resin
coated coppers (RCCs) or the flexible copper clad laminates (FCCLs)
on a substrate having a circuit pattern formed therein.
[0018] According to a preferred embodiment of the present
invention, there is provided an insulating film for a printed
circuit board including: an insulating layer; and a primer layer
formed on one surface of the insulating layer and including a
benzocyclobutene (BCB)-based resin.
[0019] The insulating layer may include a liquid-crystal oligomer,
an epoxy resin, and an inorganic filler, and the primer layer may
include the benzocyclobutene (BCB)-based resin and the epoxy
resin.
[0020] The insulating layer may include the liquid-crystal oligomer
in an amount of 4 to 30 wt %, the epoxy resin in an amount of 5 to
30 wt %, and the inorganic filler in an amount of 40 to 90 wt
%.
[0021] The primer layer may include the benzocyclobutene
(BCB)-based resin in an amount of 50 to 80 wt % and the epoxy resin
in an amount of 20 to 50 wt %.
[0022] The primer layer may include the benzocyclobutene
(BCB)-based resin in an amount of 60 to 70 wt % and the epoxy resin
in an amount of 30 to 40 wt %.
[0023] The epoxy resin included in the insulating layer or the
primer layer may be at least one selected from a group consisting
of a naphthalene-based epoxy resin, a bisphenol A type epoxy resin,
a phenol novolak epoxy resin, a cresol novolak epoxy resin, a
rubber-modified epoxy resin, a phosphorus-based epoxy resin, and a
bisphenol F type epoxy resin.
[0024] The inorganic filler may be at least one selected from a
group consisting of silica (SiO.sub.2), alumina (Al.sub.2O.sub.3),
silicon carbide (SiC), barium sulfate (BaSO.sub.4), talc, clay,
mica powder, aluminum hydroxide (AlOH.sub.3), magnesium hydroxide
(Mg(OH).sub.2), calcium carbonate (CaCO.sub.3), magnesium carbonate
(MgCO.sub.3), magnesium oxide (MgO), boron nitride (BN), aluminum
borate (AlBO.sub.3), barium titanate (BaTiO.sub.3), calcium
zirconate (CaZrO.sub.3), and a combination thereof.
[0025] The inorganic filler included in the insulating layer may
have a concentration gradient in a thickness of the insulating
layer, and have a higher concentration distribution in a region
distant from the primer layer than in a region adjacent to the
primer layer in the insulating layer.
[0026] The primer layer may have a thickness in a range of 1 .mu.m
to 3 .mu.m.
[0027] The insulating layer or the primer layer may further include
a curing agent, a curing accelerator, or a combination thereof.
[0028] The curing agent may be at least one selected from a group
consisting of an amine-based curing agent, an acid anhydride-based
curing agent, a polyamine curing agent, a polysulfide curing agent,
a phenol novolak type curing agent, a bisphenol A type curing
agent, and a dicyandiamide curing agent.
[0029] The curing accelerator may be at least one selected from a
group consisting of a metal-based curing accelerator, an
imidazole-based curing accelerator, and an amine-based curing
accelerator.
[0030] The primer layer may be formed by directly applying a primer
solution on the insulating layer or casting the primer solution on
a carrier film and then laminating and transferring the primer
solution on the insulating layer.
[0031] According to another preferred embodiment of the present
invention, there is provided a resin coated copper (RCC) or a
flexible copper clad laminate (FCCL) manufactured by stacking and
laminating copper clad layers on the primer layer of the insulating
film for a printed circuit board as described above.
[0032] According to another preferred embodiment of the present
invention, there is provided a printed circuit board manufactured
by stacking and laminating the resin coated copper (RCC) or the
flexible copper clad laminate (FCCL) as described above on a
substrate having a circuit pattern formed therein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The above and other objects, features and advantages of the
present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0034] FIG. 1 is a cross-sectional view of an insulating film for a
printed circuit board according to a preferred embodiment of the
present invention;
[0035] FIG. 2 is a cross-sectional view of an insulating film for a
printed circuit board according to another preferred embodiment of
the present invention;
[0036] FIG. 3 is a cross-sectional view of a resin coated copper
(RCC) having an insulating film for a printed circuit board
according to another preferred embodiment of the present invention;
and
[0037] FIG. 4 is a cross-sectional view of a flexible copper clad
laminate (FCCL) having the insulating film for the printed circuit
board according to another preferred embodiment of the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] The objects, features and advantages of the present
invention will be more clearly understood from the following
detailed description of the preferred embodiments taken in
conjunction with the accompanying drawings. Throughout the
accompanying drawings, the same reference numerals are used to
designate the same or similar components, and redundant
descriptions thereof are omitted. Further, in the following
description, the terms "first", "second", "one side", "the other
side" and the like are used to differentiate a certain component
from other components, but the configuration of such components
should not be construed to be limited by the terms. Further, in the
description of the present invention, when it is determined that
the detailed description of the prior art would obscure the gist of
the present invention, the description thereof will be omitted.
[0039] Hereinafter, preferred embodiments of the present invention
will be described in detail with reference to the attached
drawings.
[0040] FIG. 1 is a cross-sectional view of an insulating film for a
printed circuit board according to a preferred embodiment of the
present invention, and FIG. 2 is a cross-sectional view of an
insulating film for a printed circuit board according to another
preferred embodiment of the present invention.
[0041] Referring to FIGS. 1 and 2, the insulating films for the
printed circuit board 10 and 20 according to the preferred
embodiment of the present invention include insulating layers 110
and 210 including an inorganic filler; and primer layers 150 and
250 formed on one surface of the insulating layers 110 and 210 and
including a benzocyclobutene (BCB)-based resin. The primer layers
150 and 250 may contain the benzocyclobutene (BCB)-based resin
having significant adhesion with a metal, such that a roughening
process, or the like, may not be needed, the convenience of the
process may be improved, and a plating adhesion may be stably
secured. In addition, a resin coated copper (RCC), a flexible
copper clad laminate (FCCL), and a printed circuit board including
the insulating films 10 and 20 may be provided.
[0042] First, the insulating layers 110 and 210 of the insulating
films 10 and 20 for the printed circuit board according to the
preferred embodiment of the present invention may include an epoxy
resin, and inorganic fillers 120 and 220. In addition, the
insulating layers 110 and 210 may further include a liquid-crystal
oligomer, or the like, in consideration of thermal, mechanical, and
electrical properties.
[0043] The epoxy resin used in the insulating layers 110 and 210
may be at least one selected from a group consisting of a
naphthalene-based epoxy resin, a bisphenol A type epoxy resin, a
phenol novolak epoxy resin, a cresol novolak epoxy resin, a
rubber-modified epoxy resin, a phosphorus-based epoxy resin and a
bisphenol F type epoxy resin, and the naphthalene-based epoxy resin
or the bisphenol A type epoxy resin is preferred.
[0044] An amount of epoxy resin used in the insulating layers 110
and 210 in the insulating films 10 and 20 according to the
preferred embodiment of the present invention is not particularly
limited, but for example, the amount thereof may be 10 to 20 wt %
and may be in a range of 5 to 30 wt %. In the case in which the
used amount of epoxy resin is less than 5 wt %, peel strength may
be deteriorated, and in the case in which the used amount thereof
is more than 30 wt %, a coefficient of thermal expansion will be
increased. In addition, the insulating layer may include the
liquid-crystal oligomer, and/or a filler, for example, an inorganic
filler. Here, the liquid-crystal oligomer may be included in an
amount of 4 to 30 wt % in order to decrease the coefficient of
thermal expansion of the film.
[0045] As the inorganic fillers 120 and 220, silica (SiO.sub.2),
alumina (Al.sub.2O.sub.3), silicon carbide (SiC), barium sulfate
(BaSO.sub.4), talc, clay, mica powder, aluminum hydroxide
(AlOH.sub.3), magnesium hydroxide (Mg(OH).sub.2), calcium carbonate
(CaCO.sub.3), magnesium carbonate (MgCO.sub.3), magnesium oxide
(MgO), boron nitride (BN), aluminum borate (AlBO.sub.3), barium
titanate (BaTiO.sub.3), and calcium zirconate (CaZrO.sub.3) may be
used alone or two kinds or more may be combined with each other.
The inorganic fillers 120 and 220 are not particularly limited, but
an average particle diameter thereof is preferably 0.05 to 2 .mu.m,
and the same kind or two kinds of inorganic filler may be used.
[0046] The amount of inorganic fillers 120 and 220 used in the
insulating layers 110 and 120 in the insulating films 10 and 20
according to the preferred embodiment of the present invention is
40 to 90 wt %, preferably 60 to 90 wt %, more preferably 70 to 90
wt %, and most preferably 80 to 90 wt %. In the case in which the
used amount of inorganic fillers 120 and 220 is less than 40 wt %,
a dielectric property may be decreased and the coefficient of
thermal expansion may be increased, and in the case in which the
used amount thereof is more than 90 wt %, the peel strength may be
deteriorated.
[0047] Meanwhile, the insulating films 10 and 20 according to the
embodiments of the present invention shown in FIGS. 1 and 2 have
different distribution of the inorganic fillers 120 and 220 in to
the insulating layers 110 and 210. In the insulating film 10 shown
in FIG. 1, the inorganic filler 120 is uniformly distributed in the
insulating film 110, meanwhile, in the insulating film 20 shown in
FIG. 2, the inorganic filler 220 has a different concentration
gradient in a thickness direction of the insulating layer 120.
[0048] Referring to FIG. 2, in the case in which the inorganic
filler 220 has different concentration gradient in the thickness
direction of the insulating layer 210, the inorganic filler 220 may
have a higher concentration distribution in a region distant from
the primer layer 250 than in a region adjacent to the primer layer
250 in the insulating layer 210. As described above, known methods
in the art, for example, two insulating sheets having different
concentration of the inorganic fillers are stacked, and the like,
are used and the inorganic filler 220 in the insulating layer has
the different concentration gradient, such that the coefficient of
thermal expansion property and the plating adhesion may be
improved.
[0049] Primer Layer
[0050] The primer layers 150 and 250 of the insulating films 10 and
20 according to the preferred embodiment of the present invention
may include a benzocyclobutene-based resin, a thermal curable
resin, for example, an epoxy resin, and may be formed on one
surface of the insulating layers 110 and 120. Here, the
benzocyclobutene-based resin may have low dielectric constant,
dissipation factor, coefficient of moisture-absorption, and
coefficient of thermal expansion (CTE), and excellent thermal
stability and chemical resistance to improve physical properties of
the insulating film.
[0051] In addition, a curing process is performed at a low
temperature, by-products such as water, and the like, are not
generated during a process, and planarization is excellent, such
that it is easy to manufacture a film, and a microelectronic device
having a multilayer structure may be manufactured.
[0052] The primer layers 150 and 250 of the insulating films 10 and
20 according to the preferred embodiments of the present invention
may have a thickness in a range of 1 .mu.m to 3 .mu.m. In the case
in which the general primer layer according to the prior art has a
thickness less than 3 .mu.m, the primer layer itself is destroyed
by the desmear process, such that the peel strength is deteriorated
and it is difficult to achieve a fine circuit. However, the primer
layers 150 and 250 of the insulating films 10 and 20 according to
the preferred embodiments of the present invention includes the
benzocyclobutene-based resin, such that the plating adhesion with
the copper clad layer formed on the primer layers 150 and 250 may
be improved without performing the desmear process, thereby having
a thickness in a range of 1 .mu.m to 3 .mu.m.
[0053] In addition, it is preferred that the primer layer includes
the benzocyclobutene (BCB)-based resin in an amount of 50 to 80 wt
% and the epoxy resin in an amount of 20 to 50 wt %. In the case in
which the benzocyclobutene (BCB)-based resin has an amount of 80 wt
% or more, the coefficient of thermal expansion property is
deteriorated, and in the case in which the benzocyclobutene
(BCB)-based resin has an amount less than 50 wt %, the plating
adhesion is deteriorated. Therefore, a composition of the primer
layer is controlled to improve the plating adhesion with the copper
clad layer and the coefficient of thermal expansion property,
thereby manufacturing the insulating film for the printed circuit
board.
[0054] Further, in the primer layers 150 and 250 in the insulating
films 10 and 20 according to the preferred embodiments of the
present invention, the epoxy resin may be at least one selected
from a group consisting of the naphthalene-based epoxy resin, the
bisphenol A type epoxy resin, the phenol novolak epoxy resin, the
cresol novolak epoxy resin, the rubber-modified epoxy resin, the
phosphorus-based epoxy resin and the bisphenol F type epoxy resin,
and the naphthalene-based epoxy resin or the bisphenol A type epoxy
resin is preferred.
[0055] In the preferred embodiment of the present invention, a
curing agent, a curing accelerator, or a combination thereof may be
selective used in the insulating layers 110 and 210 or the primer
layers 150 and 250 in the insulating films 10 and 20 for the
printed circuit board.
[0056] Any curing agent may be generally used as long as the curing
agent includes a reacting group which is capable of reacting with
an epoxide ring included in the epoxy resin, but is not
particularly limited. More specifically, examples of the curing
agent may include an amine-based curing agent, an acid
anhydride-based curing agent, a polyamine curing agent, a
polysulfide curing agent, a phenol novolak type curing agent, a
bisphenol A type curing agent and a dicyandiamide curing agent, and
one kind or a combination of two or more kinds of curing agent may
be used. The used amount of curing agent may be appropriately
selected in a range of 0.1 to 1 part by weight with respect to 100
parts by weight of the insulating layers 110 and 210 or the primer
layers 150 and 250 in consideration of a curing rate without
deteriorating physical properties.
[0057] Examples of the curing accelerator may include a metal-based
curing accelerator, an imidazole-based curing accelerator and an
amine-based curing accelerator, and one kind or a combination of
two or more kinds of a curing accelerator may be used.
[0058] Examples of the metal-based curing accelerator may include
an organic metal complex or an organic metal salt of a metal such
as cobalt, copper, zinc, iron, nickel, manganese, tin, or the like,
but the present invention is not specifically limited thereto.
Specific examples of the organic metal complex may include organic
cobalt complex such as cobalt (II) acetylacetonate, cobalt (III)
acetylacetonate, or the like, organic copper complex such as copper
(II) acetylacetonate, organic zinc complex such as zinc (II)
acetylacetonate, organic iron complex such as iron (III)
acetylacetonate, organic nickel complex such as Ni (II)
acetylacetonate, organic manganese complex such as manganese (II)
acetylacetonate, and the like. Examples of the organic metal salt
may include zinc octyl acid, tin octyl acid, zinc naphthenic acid,
cobalt naphthenic acid, tin stearic acid, zinc stearic acid, and
the like. As the metal-based curing accelerator, cobalt (II)
acetylacetonate, cobalt (III) acetylacetonate, zinc (II)
acetylacetonate, zinc naphthenic acid, iron (III) acetylacetonate
is preferred, and in particular, cobalt (II) acetylacetonate and
zinc naphthenic acid is more preferred, in view of curability and a
solvent solubility. One kind or a combination of two or more kinds
of the metal-based curing accelerator may be used.
[0059] Examples of the imidazole-based curing accelerator may
include imidazole compounds such as 2-methylimidazole,
2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole,
2-ethyl-4-methylimidazole, 1,2-dimethylimidazole,
2-ethyl-4-methylimidazole, 2-phenylimidazole,
2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole,
1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole,
1-cyanoethyl-2-undecylimidazole,
1-cyanoethyl-2-ethyl-4-methylimidazole,
1-cyanoethyl-2-phenylimidazole,
1-cyanoethyl-2-undecylimidazoliumtrimellitate,
1-cyanoethyl-2-phenylimidazoliumtrimellitate,
2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine,
2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine,
2,4-diamino-6-[2'-ethyl4'-methylimidazolyl-(1')]-ethyl-s-triazine,
2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazineisocyanic
acid adduct, 2-phenyl-imidazoleisocyanic acid adduct,
2-phenyl-4,5-dihydroxymethylimidazole,
2-phenyl-4-methyl-5-hydroxymethylimidazole,
2,3-dihydroxy-1H-pyroro[1,2-a]benzimidazole,
1-dodecyl-2-methyl-3-benzyl-imidazoliumchloride,
2-methylimidazoline, and 2-phenyl-imidazoline, and an adduct of the
imidazole compounds and the epoxy resin, but the present invention
is not particularly limited thereto. One kind or a combination of
two or more kinds of the imidazole-based curing accelerator may be
used.
[0060] Examples of the amine-based curing accelerator may include
trialkylamine such as triethylamine and tributylamine, and an amine
compound such as 4-dimethylaminopyridine, benzyldimethylamine,
2,4,6-tris(dimethylamino-methyl)phenol,
1,8-diazabicyclo(5,4,0)-undecene, but the present invention is not
specifically limited thereto. One kind or a combination of two or
more kinds of the amine-based curing accelerator may be used.
[0061] FIG. 3 is a view showing a resin coated copper (RCC) having
the insulating film for the printed circuit board according to
another preferred embodiment of the present invention, and FIG. 4
is view showing a flexible copper clad laminate (FCCL) having the
insulating film for the printed circuit board according to another
preferred embodiment of the present invention.
[0062] As shown in FIGS. 3 and 4, the insulating films 30 and 40
according to the preferred embodiment of the present invention and
the RCC 3 and the FCCL 4 manufactured by using the same are
laminated on a copper clad laminate (CCL) used as an inner layer at
the time of manufacturing a multilayer printed circuit board and
are used in manufacturing the multilayer printed circuit board.
[0063] That is, the printed circuit board is largely classified
into the insulating layers 310 and 410 and the copper clad layers
370 and 470. In addition, in the printed circuit board, the copper
clad layer is formed on at least one surface of the insulating
layer, and again the insulating layer is formed on the copper clad
layer by using a build-up film, and then the copper clad layer is
again formed, thereby configuring continuous build-up layers. The
printed circuit board may include a capacitor, a resistor, or other
electronic components as needed, and the outermost thereof may be
provided with a solder resist layer in order to protect the circuit
board. The printed circuit board may be provided with external
connection units according to electronic products to be mounted
thereon, and sometimes provided with a pad layer. The printed
circuit board manufactured by the preferred embodiment of the
present invention may have excellent coefficient of thermal
expansion property and excellent peel strength between the
insulating layer and the copper clad layer.
[0064] Hereinafter, the present invention will be described in more
detail with reference to the following Examples and Comparative
Examples; however, it is not limited thereto.
EXAMPLE 1
[0065] Preparation of Insulating Layer
[0066] A liquid-crystal oligomer 6 g containing a hydroxyl group at
an end portion thereof was added to N,N'-dimethylacetamide (DMAc) 6
g to prepare a liquid-crystal oligomer solution, and a silica
(SiO.sub.2) slurry 102.41 g was added thereto, followed by stirring
for 30 minutes. An epoxy resin Araldite MY-721 (Huntsman
Corporation) 8 g was added to the reactant, followed by stirring
for 1 hour. Then, dicyandiamide (DICY) 0.08 g and
azobisbutyronitrile (AIBN) 0.09 g were added to the reactant,
followed by additional stirring for 30 minutes. The reactant was
applied to a shiny copper clad surface by a doctor blade scheme so
as to have a thickness of about 80 .mu.m to manufacture a film, and
the film was dried in the oven at 80.degree. C. and 120.degree. C.
for 30 minutes, respectively, to be manufactured in a semi-cured
(B-stage) state.
[0067] Preparation of Primer Layer
[0068] N,N'-dimethylacetamide (DMAc) 4 g was added to a
benzocyclobutene-based resin 43.64 g containing a carboxylic group
at an end portion thereof and dissolved into N,N'-dimethylacetamide
(DMAc) and then 4-functional group naphthylene-based epoxy resin
(HP-4710, DIC) 3 g was added thereto, followed by stirring for 1
hour. The reactant was applied to a shiny copper clad surface by a
doctor blade scheme so as to have a thickness of about 3 .mu.m to
manufacture a film, and the film was dried in the oven at
80.degree. C. and 120.degree. C. for 30 minutes, respectively, to
be manufactured in a semi-cured (B-stage) state.
[0069] Preparation of Insulating Film
[0070] Each of the primer layers was stacked on one surface of the
insulating layer including the inorganic filler, or was directly
transferred on the insulating layer, and a primary reaction was
performed by using a vacuum press to manufacture the film in the
semi-cured (B-stage) state.
[0071] Here, the primer layer may contain the
benzocyclobutene-based resin as a main component and cause a
reaction as shown in the following Reaction Formula 1 through a
photocurable reaction or a curable reaction.
##STR00001##
[0072] In Reaction Formula 1, the copper clad layer was plated on
the primary reacted primer layer by an electroless plating method,
and the primer layer was then completely cured by a secondary
reaction as shown in the following Reaction Formula 2 (maximum
temperature 230.degree. C., maximum pressure 2 MPa).
##STR00002##
[0073] In Reaction Formula 2, the plating adhesion may be improved
due to a photocurable or photoreactive benzocyclobutene-based resin
having an interconnected network structure by a ring-opening
reaction and a diels-Alder reaction of the benzocyclobutene-based
resin.
EXAMPLE 2
[0074] A first insulating film including the insulating film having
a film thickness of about 40 .mu.m was manufactured according to
Example 1, and a second insulating film including the insulating
film having a film thickness of about 40 .mu.m, the second
insulating film having the silica (SiO.sub.2) slurry 50 g of the
insulating layer, was manufactured according to Example 1, thereby
stacking the manufactured first and second insulating films to
manufacture an insulating film having a different concentration
gradient. Here, the primer layer was used as the same as Example 1,
and formed on the first insulating film including the inorganic
filler at a low concentration. Other experimental conditions except
for the above-described conditions were the same as Example 1.
COMPARATIVE EXAMPLE 1
[0075] Acid modified cresolnovolak epoxyacrylate (Japanese Powder,
CCR-1591H) 150 g, a bisphenol A type epoxy resin (Momentive, EP631)
64 g, urethane acrylate (Miwon Special Drug, UA105) 18 g, and a
photoinitiator (BASF, Irgacure 184D) 3 g were dissolved into
methylethylketone 180 g and was used as the primer layer instead of
the existing primer layer used in Example 1. After a dispersant
(KYOEISHA, G700) 3 g was firstly mixed with the dissolved reactant,
the mixed reactant was casted so that the insulating layer has a
thickness of 3 .mu.m, and dried in the oven at 80.degree. C. for 10
minutes to manufacture the insulating film. In addition, a desmear
process was performed on the primer layer by using manganese
peroxide to be roughened, and the copper clad layer was formed on
the roughened primer layer. Other experimental conditions except
for the above-described conditions were the same as Example 1.
COMPARATIVE EXAMPLE 2
[0076] Acid modified epoxy acrylate cresolnovolak epoxyacrylate
(Japanese Powder, CCR-1591H) 150 g, a bisphenol A type epoxy resin
(Momentive, EP631) 64 g, urethane acrylate (Miwon special drug,
UA105) 18 g, and a photoinitiator (BASF, Irgacure 184D) 3 g were
dissolved into methylethylketone 180 g and was used as the primer
layer instead of the existing primer layer used in Example 1. After
a dispersant (KYOEISHA, G700) 3 g was firstly mixed with the
dissolved reactant, the mixed reactant was casted so that the
insulating layer has a thickness of 8 .mu.m, and dried in the oven
at 80.degree. C. for 10 minutes to manufacture the insulating film.
In addition, a desmear process was performed on the primer layer by
using manganese peroxide to be roughened, and the copper clad layer
was formed on the roughened primer layer. Other experimental
conditions except for the above-described conditions were the same
as Example 1.
EXAMPLE 3
[0077] Manufacture of Printed Circuit Board
[0078] A circuit board having an inner layer in which copper clads
are stacked on both surfaces thereof was dried at 120.degree. C.
for 30 minutes, a Morton CVA 725 vacuum laminator was used to
laminate the insulating film manufactured by Example 1 or Example 2
on both surfaces thereof for 20 seconds under the condition of
90.degree. C. and 2MPa, thereby manufacturing a printed circuit
board.
[0079] Measurement of Physical Properties
[0080] Evaluation on the insulating films manufactured by Examples
and Comparative Examples in view of physical properties is shown in
the following Table 1. In measurement and evaluation of a
coefficient of thermal expansion, the films were measured in a
temperature range of 50.degree. C. to 100.degree. C. by using a
thermo mechanical analysis (TMA), and were thermo
mechanical-analyzed by using a tension weight acceleration. A
sample was mounted on TMA, and was measured under the measurement
condition having a rising temperature rate of 5.degree. C./mins. An
average line thermal expansion rate (ppm) of coefficients of
thermal expansion (.alpha.1, Tg or less) at from 50.degree. C. up
to 100.degree. C. was calculated in the measurement of coefficient
of thermal expansion (CTE). In measurement and evaluation of a peel
strength, the peel strength between the copper clad layer and the
insulating layer was measured by using a universal testing machine
(UTM).
TABLE-US-00001 TABLE 1 Coefficient of Thermal Expansion Plated
Adhesion (CTE) (peel strength) (ppm/.degree. C.) (kgf/cm) Example 1
17.5 0.54 Example 2 16.0 0.58 Comparative 18.2 Cannot be Measured
Example 1 Comparative 18.2 0.51 Example 2
[0081] As shown in Table 1 above, the insulating films manufactured
by Examples 1 and 2 have excellent coefficient of thermal expansion
and peel strength as compared to those manufactured by Comparative
Examples 1 and 2, and in particular, the insulating film
manufactured by Example 2 shows the best results. The reason is
that in the insulating film manufactured by Example 2, the
inorganic filler has a different concentration gradient in a
thickness direction of the insulating layer, and the plating
adhesion is maintained, and the coefficient of thermal expansion
property is improved, even without performing a roughening plating
process of the primer layer on the insulating layer.
[0082] In addition, in the insulating films manufactured by the
preferred embodiment of the present invention, the
benzocyclobutene-based resin was used for the primer layer, and the
primer layers of the insulating films manufactured by Examples 1
and 2 have a thickness in a range of 1 .mu.m to 3 .mu.m, such that
the plating adhesion with the copper clad layer may be maintained
without performing the desmear process. Meanwhile, in the
insulating films manufactured by Comparative Examples 1 and 2, the
desmear process is performed on the existing primer layer to form
the plating adhesion.
[0083] In other words, when comparing Examples and Comparative
Example 2, the benzocyclobutene-based resin according to the
preferred embodiment of the present invention was used for the
primer layer, such that the plating adhesion between the copper
clad layer and the primer layer may be improved without performing
the desmear process. In addition, it was measured that the
insulating films manufactured by Examples had the plating adhesion
of 0.5 kgf/cm or more, which is higher than that of the insulating
film manufactured by Comparative Example 2.
[0084] Meanwhile, when comparing Examples and Comparative Example
1, the primer layer according to the prior art should be formed in
a thickness of 3 .mu.m or more due to the desmear process. The
reason that measurement of the plating adhesion of the insulating
film manufactured by Comparative Example 1 is not possible as shown
in Table 1 above is that the inorganic filler is exposed on the
surface of the insulating film during the desmear process and the
exposed inorganic filler deteriorates the plating adhesion with the
copper clad layer.
[0085] Therefore, since the desmear process is omitted, the process
is simplified, and the deterioration in the plating adhesion
occurring when the inorganic filler is exposed during the desmear
process is not generated, such that the insulating films
manufactured by Examples according to the preferred embodiment of
the present invention may have a thickness less than 3 .mu.m. That
is, the thickness of the insulating film may be decreased.
[0086] In addition, in the insulating film manufactured by
Comparative Example 1, the plating adhesion is deteriorated by the
inorganic filler exposed during the desmear process, such that the
content in the inorganic filler has a limitation. However, in the
insulating films manufactured by Examples according to the
preferred embodiment of the present invention, the desmear process
is not performed, such that the content in the inorganic filler may
be increased. In addition, due to the increased inorganic filler,
the coefficient of thermal expansion property may be improved.
Therefore, since the exposed inorganic filler causing the
deterioration in the plating adhesion is not generated, the content
in the inorganic filler may be increased to improve the coefficient
of thermal expansion property.
[0087] As set forth above, the insulating film for the printed
circuit board according to the preferred embodiment of the present
invention, and the RCC, the FCCL, and the printed circuit board
manufactured by using the same may have the low coefficient of
thermal expansion and the high peel strength.
[0088] Although the embodiments of the present invention have been
disclosed for illustrative purposes, it will be appreciated that
the present invention is not limited thereto, and those skilled in
the art will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention.
[0089] Accordingly, any and all modifications, variations or
equivalent arrangements should be considered to be within the scope
of the invention, and the detailed scope of the invention will be
disclosed by the accompanying claims.
* * * * *